Fine Needle Elastography (FNE) device for biomechanically determining local variations of tissue mechanical properties

The impact of anthropometric parameters and sonographic characteristics on the choice of biopsy method for thyroid nodules: Fine-needle aspiration versus non-aspiration biopsy

Objective

The accurate diagnosis of thyroid nodules is crucial for effective management and the detection of malignancy. Fine-needle aspiration biopsy (FNAB) and fine-needle non-aspiration biopsy (FNNAB) are widely used techniques for evaluating thyroid nodules. In this study, we aimed to investigate the impact of anthropometric parameters and sonographic characteristics on the choice between FNAB and FNNAB in terms of diagnostic yield.

Material and Methods

This retrospective and cross-sectional analysis involved 188 cases with a total of 225 thyroid nodules. Each nodule initially underwent either FNAB or FNNAB and if the initial biopsy did not yield a diagnostic result, the nodule was re-biopsied using the alternate technique. Ultrasound was used to evaluate the nodules, with a focus on echogenicity, calcifications, size, vascularity, and the presence of a halo sign. Both FNAB and FNNAB were performed using a 25-gauge needle, with the only difference being the application of suction.

Results

FNAB demonstrated a higher diagnostic rate for nodules with a taller-than-wide shape (anteroposteriorto-transverse ratio ≥1), nodules sized 10-40 mm, nodules with volumes <0.5 cc, and hypoechoic nodules (P < 0.001 for all). FNAB also outperformed FNNAB in the assessment of the right-sided, inferior, and posterior nodules (P < 0.001), nodules with and without calcification (P = 0.041 and P = 0.020, respectively), and nodules with type 1 and type 2 vascularity patterns (P = 0.006 and P = 0.017, respectively). FNAB was effective in obese individuals (Body mass index ≥40 kg/m2), males with a waist circumference of <94 cm, females with a waist circumference of ≥80 cm, and females with a neck circumference of ≥34 cm (P = 0.011, P = 0.044, P = 0.029, and P = 0.008, respectively).

Conclusion

Anthropometric parameters and sonographic characteristics influenced the diagnostic yield of FNAB and FNNAB, with FNAB generally demonstrating superior results. Given the importance of obtaining an accurate diagnostic result from fine-needle biopsy, clinicians should consider both the sonographic features of the nodule and the anthropometric measurements of the patient when selecting a biopsy technique.

Recent advances in microsystem approaches for mechanical characterization of soft biological tissues

Microsystem technologies for evaluating the mechanical properties of soft biological tissues offer various capabilities relevant to medical research and clinical diagnosis of pathophysiologic conditions. Recent progress includes (1) the development of tissue-compliant designs that provide minimally invasive interfaces to soft, dynamic biological surfaces and (2) improvements in options for assessments of elastic moduli at spatial scales from cellular resolution to macroscopic areas and across depths from superficial levels to deep geometries. This review summarizes a collection of these technologies, with an emphasis on operational principles, fabrication methods, device designs, integration schemes, and measurement features. The core content begins with a discussion of platforms ranging from penetrating filamentary probes and shape-conformal sheets to stretchable arrays of ultrasonic transducers. Subsequent sections examine different techniques based on planar microelectromechanical system (MEMS) approaches for biocompatible interfaces to targets that span scales from individual cells to organs. One highlighted example includes miniature electromechanical devices that allow depth profiling of soft tissue biomechanics across a wide range of thicknesses. The clinical utility of these technologies is in monitoring changes in tissue properties and in targeting/identifying diseased tissues with distinct variations in modulus. The results suggest future opportunities in engineered systems for biomechanical sensing, spanning a broad scope of applications with relevance to many aspects of health care and biology research.

Cancer cell mechanobiology: a new frontier for cancer research

The study of physical and mechanical features of cancer cells, or cancer cell mechanobiology, is a new frontier in cancer research. Such studies may enhance our understanding of the disease process, especially mechanisms associated with cancer cell invasion and metastasis, and may help the effort of developing diagnostic biomarkers and therapeutic drug targets. Cancer cell mechanobiological changes are associated with the complex interplay of activation/inactivation of multiple signaling pathways, which can occur at both the genetic and epigenetic levels, and the interactions with the cancer microenvironment. It has been shown that metastatic tumor cells are more compliant than morphologically similar benign cells in actual human samples. Subsequent studies from us and others further demonstrated that cell mechanical properties are strongly associated with cancer cell invasive and metastatic potential, and thus may serve as a diagnostic marker of detecting cancer cells in human body fluid samples. In this review, we provide a brief narrative of the molecular mechanisms underlying cancer cell mechanobiology, the technological platforms utilized to study cancer cell mechanobiology, the status of cancer cell mechanobiological studies in various cancer types, and the potential clinical applications of cancer cell mechanobiological study in cancer early detection, diagnosis, and treatment.

Piezoelectric needle sensor reveals mechanical heterogeneity in human thyroid tissue lesions

Palpable thyroid lesions are common, and although mostly benign, lethal malignant nodules do occur and may be difficult to differentiate. Here, we introduce the use of a piezoelectric system called Smart-touch fine needle (or STFN) mounted directly onto conventional biopsy needles, to evaluate abnormal tissues, through quantitative real-time measurements of variations in tissue stiffness as the needle penetrates tissue. Using well-characterized biomaterials of known stiffness and explanted animal tissue models, we first established experimental protocols for STFN measures on biological tissues, as well as optimized device design for high signal-to-noise ratio. Freshly excised patient thyroids with varying fibrotic and malignant potential revealed discrete variations in STFN based tissue stiffness/stiffness heterogeneity and correlated well with final histopathology. Our piezoelectric needle sensor reveals mechanical heterogeneity in thyroid tissue lesions and provides a foundation for the design of hand-held tools for the rapid, mechano-profiling of malignant lesions in vivo while performing fine needle aspiration (FNA).

Length Scale Matters: Real-Time Elastography versus Nanomechanical Profiling by Atomic Force Microscopy for the Diagnosis of Breast Lesions

Real-time elastography (RTE) is a noninvasive imaging modality where tumor-associated changes in tissue architecture are recognized as increased stiffness of the lesion compared to surrounding normal tissue. In contrast to this macroscopic appraisal, quantifying stiffness properties at the subcellular level by atomic force microscopy (AFM) reveals aggressive cancer cells to be soft. We compared RTE and AFM profiling of the same breast lesion to explore the diagnostic potential of tissue elasticity at different length scales. Patients were recruited from women who were scheduled for a biopsy in the outpatient breast clinic of the University Hospital Basel, Switzerland. RTE was performed as part of a standard breast work-up. Individual elastograms were characterized based on the Tsukuba elasticity score. Additionally, lesion elasticity was semiquantitatively assessed by the strain ratio. Core biopsies were obtained for histologic diagnosis and nanomechanical profiling by AFM under near-physiological conditions. Bulk stiffness evaluation by RTE does not always allow for a clear distinction between benign and malignant lesions and may result in the false assessment of breast lesions. AFM on the other hand enables quantitative stiffness measurements at higher spatial, i.e., subcellular, and force resolution. Consequently, lesions that were false positive or false negative by RTE were correctly identified by their nanomechanical AFM profiles as confirmed by histological diagnosis. Nanomechanical measurements can be used as unique markers of benign and cancerous breast lesions by providing relevant information at the molecular level. This is of particular significance considering the heterogeneity of tumors and may improve diagnostic accuracy compared to RTE.

Targeting Biophysical Cues: a Niche Approach to Study, Diagnose, and Treat Cancer

Probing the biophysical properties of the tumor niche offers a new perspective in cancer mechanobiology, and supports the development of next-generation diagnostics and therapeutics for cancer, in particular for metastasis.

Needle-shaped ultrathin piezoelectric microsystem for guided tissue targeting via mechanical sensing

Needles for percutaneous biopsies of tumour tissue can be guided by ultrasound or computed tomography. However, despite best imaging practices and operator experience, high rates of inadequate tissue sampling, especially for small lesions, are common. Here, we introduce a needle-shaped ultrathin piezoelectric microsystem that can be injected or mounted directly onto conventional biopsy needles and used to distinguish abnormal tissue during the capture of biopsy samples, through quantitative real-time measurements of variations in tissue modulus. Using well-characterized synthetic soft materials, explanted tissues and animal models, we establish experimentally and theoretically the fundamental operating principles of the microsystem, as well as key considerations in materials choices and device designs. Through systematic tests on human livers with cancerous lesions, we demonstrate that the piezoelectric microsystem provides quantitative agreement with magnetic resonance elastography, the clinical gold standard for the measurement of tissue modulus. The piezoelectric microsystem provides a foundation for the design of tools for the rapid, modulus-based characterization of tissues.

Risk of malignancy in thyroid nodules: predictive value of puncture feeling of grittiness in the process of fine-needle aspiration

Fine-needle aspiration cytology (FNAC) is widely used for diagnosing thyroid nodules. However, there has been no specific investigation about the puncture feeling of grittiness. The aim of the present study was to see if the puncture feeling of grittiness during fine-needle aspiration procedure, combined with standard FNAC, could improve the accuracy in diagnosing thyroid cancer. A total of one thousand five hundred and thirty-one thyroid FNAC specimens acquired between January 2013 and January 2017 were retrospectively retrieved. All cases underwent surgical intervention. The FNAC diagnoses and puncture feeling of grittiness were evaluated and compared with the results of final histopathological diagnoses. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of diagnosis for thyroid nodules by FNAC alone, puncture feeling of grittiness alone, and the combination of FNAC plus grittiness were calculated respectively. The findings of our study suggest that puncture feeling of grittiness is a useful adjunct. Adding puncture feeling of grittiness to FNAC can significantly enhance the ability to differentiate malignant thyroid nodules from benign thyroid nodules. More importantly, we found that puncture feeling of grittiness is surprising trust-worthy in being near perfectly reproducible per individual radiologist, and among different operators.